The concern over the potential hazards of low level radiation exposure is increasing as the understanding of its biological effects increases, particularly in assessing the risk to personnel who receive occupational exposure to radiation. Current radiation risk assessment methods use global, nonstochastic quantities, i.e., large mass or volume averaged quantities, to characterize radiation and its biological effects. This approach cannot be used to measure and understand the effects at the cellular level. The problem with this is that most medical problems caused by radiation exposure are due to damage to individual cells. Thus, to understand the mechanisms causing the damage, it is necessary to develop new sensors to measure interactions at that microscopic cellular level. Existing detector technology is not adequate for making microdosimetric measurements. New types of detectors are needed to fill the need both for research and for personnel monitoring. This research effort will investigate the fabrication of tissue equivalent, solid state detectors for use in microdosimetry.